A fake explanation is anything which sounds like an explanation, or is offered as an explanation, but which does not offer any further understanding even if it might be true.
"Because God did it" is one example commonly used in religion-based arguments. The question-and-answer pair "What makes it go? Energy!", found in an elementary school science textbook, was derided by the late Nobel Prize-winning physicist Richard Feynman as being utterly useless as an explanation.